Number

8,821

8,821 is a prime, odd.

8,821 (eight thousand eight hundred twenty-one) is an odd 4-digit number. It is a prime number — divisible only by 1 and itself. Written other ways, in hexadecimal, 0x2275.

Arithmetic Number Cube-Free Deficient Number Happy Number Odious Number Pernicious Number Prime Pythagorean Prime Recamán's Sequence Squarefree Twin Prime

Interestingness

★ ★ ★ ★ ★

8 notable facts · grade A

8,809 8,810 8,811 8,812 8,813 8,814 8,815 8,816 8,817 8,818 8,819 8,820 8,821 8,822 8,823 8,824 8,825 8,826 8,827 8,828 8,829 8,830 8,831 8,832 8,833

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Properties

Parity: Odd
Digit count: 4
Digit sum: 19
Digit product: 128
Digital root: 1
Palindrome: No
Bit width: 14 bits
Reversed: 1,288
Recamán's sequence: a(24,954) = 8,821
Square (n²): 77,810,041
Cube (n³): 686,362,371,661
Divisor count: 2
σ(n) — sum of divisors: 8,822
φ(n) — Euler's totient: 8,820

Primality

8,821 is prime. It has exactly two divisors: 1 and itself.

Divisors & multiples

All divisors (2)

1 · 8821

Aliquot sum (sum of proper divisors): 1

Factor pairs (a × b = 8,821)

1 × 8821

First multiples

8,821 · 17,642 (double) · 26,463 · 35,284 · 44,105 · 52,926 · 61,747 · 70,568 · 79,389 · 88,210

Sums & aliquot sequence

As a sum of two squares: 30² + 89²

As consecutive integers: 4,410 + 4,411

Continued fraction of √n

√8,821 = [93; (1, 11, 1, 1, 8, 2, 2, 1, 4, 1, 1, 1, 8, 1, 2, 1, 14, 1, 10, 8, 1, 5, 1, 4, …)]

Representations

In words: eight thousand eight hundred twenty-one
Ordinal: 8821st
Binary: 10001001110101
Octal: 21165
Hexadecimal: 0x2275
Base64: InU=
One's complement: 56,714 (16-bit)
Scientific notation: 8.821 × 10³
As a duration: 8,821 s = 2 hours, 27 minutes, 1 second

In other bases

ternary (3) 110002201

quaternary (4) 2021311

quinary (5) 240241

senary (6) 104501

septenary (7) 34501

nonary (9) 13081

undecimal (11) 669a

duodecimal (12) 5131

tridecimal (13) 4027

tetradecimal (14) 3301

pentadecimal (15) 2931

As an angle

8,821° = 24 × 360° + 181°

181° ≈ 3.159 rad

Compass bearing: S (south)

Why does a circle have 360 degrees? →

Historical numeral systems

Babylonian (base 60): 𒁹𒁹 𒌋𒌋𒁹𒁹𒁹𒁹𒁹𒁹𒁹 𒁹
Egyptian hieroglyphic: 𓆼𓆼𓆼𓆼𓆼𓆼𓆼𓆼𓍢𓍢𓍢𓍢𓍢𓍢𓍢𓍢𓎆𓎆𓏺
Greek (Milesian): ͵ηωκαʹ
Mayan (base 20): 𝋡·𝋢·𝋡·𝋡
Chinese: 八千八百二十一
Chinese (financial): 捌仟捌佰貳拾壹

In other modern scripts

Eastern Arabic ٨٨٢١ Devanagari ८८२१ Bengali ৮৮২১ Tamil ௮௮௨௧ Thai ๘๘๒๑ Tibetan ༨༨༢༡ Khmer ៨៨២១ Lao ໘໘໒໑ Burmese ၈၈၂၁

Digit at this position in famous constants

π — Pi (π): Digit 8,821 = 1
e — Euler's number (e): Digit 8,821 = 7
φ — Golden ratio (φ): Digit 8,821 = 1
√2 — Pythagoras's (√2): Digit 8,821 = 8
ln 2 — Natural log of 2: Digit 8,821 = 5
γ — Euler-Mascheroni (γ): Digit 8,821 = 2

Also seen as

Prime neighborhood

Adjacent primes:

Previous prime: 8,819 (gap of 2)
Next prime: 8,831 (gap of 10)

Pair status: twin with 8819.

Unicode codepoint

≵

Neither Greater-Than Nor Equivalent To

U+2275

Math symbol (Sm)

UTF-8 encoding: E2 89 B5 (3 bytes).

Lookup U+2275 on Compart ↗ Lookup on FileFormat.Info ↗

Hex color

#002275

RGB(0, 34, 117)

IPv4 address

As an unsigned 32-bit integer, this is the IPv4 address 0.0.34.117.

Address: 0.0.34.117
Class: reserved
IPv4-mapped IPv6: ::ffff:0.0.34.117

Unspecified address (0.0.0.0/8) — "this network" placeholder.

Musical pitch

Heard as a frequency, 8,821 Hz is closest to:

Concert pitch (A4 = 440 Hz): C♯9 (8869.8 Hz, -10¢)
Scientific pitch (C4 = 256 Hz): C♯9 (8679.1 Hz, +28¢)
Baroque pitch (A4 = 415 Hz): D9 (8863.3 Hz, -8¢)

Position in π

The digit sequence 8821 first appears in π at position 28,327 of the decimal expansion (the 28,327ordinal-suffix:th digit after the integer 3).

Search range: the first 1,000,000 fractional digits of π. Any 6-digit-or-shorter string is virtually guaranteed to appear in there — the more interesting signal is the position.

Look up 8821 on Pi Search ↗